Viral diseases inflict man, plants, insects, and animals. The prevention and control of viral diseases have important health and economic implications.
Viral diseases contribute to inflictions in humans including common colds, herpes and cancer and the importance of their control is obvious. Also important is control of viral diseases in animals for economic reasons as well as the ability of such animals to become virus reservoirs or carriers which facilitate the spreading of viral diseases to humans. Viral plant diseases disrupt the cultivation of fruit trees, tobacco, and various vegetables. Insect viral diseases are also of interest because of the insects' ability to transfer viral diseases to other hosts.
The prevention and control of viral diseases is thus of prime importance to man and considerable research has been devoted to antiviral measures. Certain methods and chemical compositions have been developed which aid in inhibiting, controlling or destroying viruses but new methods and antiviral chemical compositions are needed.
U.S. Pat. Nos. 4,162,308 and 4,162,309 to Calvin and Ellis describe that water soluble extract from marine red alga have been found to be effective to inhibit the growth of certain herpes viruses.
U.S. Pat. No. 4,162,308 describes water soluble attracts from marine red alga selected from a group consisting of Turnerella mertensiana, Schizymenia epiphytica, Turnerella pennyi algae and mixtures thereof as effective to inhibit the growth of herpes simplex virus, type 1 and type 2, and herpes zoster, and to relieve the pain caused by infection attributable to such viruses.
U.S. Pat. No. 4,162,309 describes the use of water soluble extracts from marine red alga selected from a group consisting of Neodilsea americana and Neodilsea integra algae and mixtures thereof to inhibit the growth of herpes simplex virus, type 1 and type 2, and herpes zoster, and to relieve the pain caused by infection attributable to such viruses. The entire disclosures of U.S. Pat. Nos. 4,162,308 and 4,162,309 are hereby incorporated herein by reference.
In addition to the water soluble red alga extracts described in the above noted U.S. patent applications to Calvin and Ellis other compounds have been isolated from red alga and marine organisms known as sea hares which are mollusks which diet on red algae. These compounds include halogenated chamigrenes and have been described in various literature references including P. J. Scheuer, Ed. Marine Natural Products Volume 1 (Martin) and Volume 5 (Erickson) Acedemic Press, 1978, 1983 the entire disclosure of this reference is hereby incorporated herein by reference. Halogenated chamigrenes have also been disclosed by Dr. Tatsuo Higa in a speech given in Japan in October of 1984, the entire disclosure of the Japanese abstract is hereby made of record and incorporated by reference, herein.
A co-pending application of the present inventors filed concurrently herewith relates to red alga extracts comprising certain cyclohexadienones which show antiviral activity.
It has now been found that certain chamigrene extracts from marine organisms such as sea hares which diet upon red alga, possess useful antiviral activity.